The present invention relates to plastic bags which are used as liners for waste receptacles and the like. More particularly it relates to such plastic liner bags which include an integral feature to retain the liner in place within the receptacle.
The use of appropriately sized plastic bags as waste receptacle liners has become a common practice in recent years. Because of sanitary and economic consideration, the practice of using plastic bags to line waste receptacles has become standard in most institutional and commercial settings. In addition, plastic bags are also used to line receptacles for soiled laundry and other materials which are collected in a like receptacle.
The plastic liner bags serve at least two important functions. First, the liner prevents the waste or other material from contacting the receptacle, thus avoiding the necessity of cleaning the receptacle. Second, the receptacle can be emptied in an easy fashion by simply pulling the liner full of waste or other material out of the receptacle. This is not only a simpler task for the user emptying the receptacle, but is also more sanitary as it allows the user to better avoid contact with the waste or other material.
A common problem which has hindered the use of plastic bags as waste receptacle liners has been the tendency of the bags have to slide down within the receptacle. That is, even though the top of the bag is folded over the sides of the receptacle, as waste material is placed in the receptacle, the sides of the bag tend to be pulled down. As a result, the bag ends up in a heap at the bottom of the receptacle and thus fails to provide either of the two functions mentioned above.
Several attempts have been made to solve this problem. For example, some bags are designed to be much taller than the receptacle so that more bag can be folded over the top. However, although this may help, it cannot insure that the bag will not slip down. In addition, it is unsightly to have too much bag hanging out of the receptacle.
As another example, waste receptacles have been designed with lids which clamp over the top of the receptacle, thus clamping the top of the bag in place. Naturally, this lid adds expense to the cost of the receptacle and makes installation and removal of the bag more complex and time consuming.
Other examples have been observed. Some bags are maintained in place by gathering part of the top of the bag, drawing it over the rim of the receptacle, and then tying it in a knot. Other bags are maintained in place by tying a string or placing a large rubber band around the top portion of the part which is hanging over the rim of the receptacle. Still other bags are maintained in place by using tape or some other adhesive to attach the top portion of the bag to the receptacle.
In the case of some liner bags, the slight elasticity of the plastic itself will aid in holding the bag in place. That is, some bags will stretch to a small extent so that they are held tightly when folded over the rim of the receptacle. However, the elasticity of the typical liner bag is relatively low and the bags will often tear when pulled too hard. In addition, high density polyethylene, a material which possesses high strength at low cost and would thus be an excellent material for making liner bags, has almost no elasticity.
U.S. Pat. No. 4,509,570 to Eby et al. describes a plastic trash bag which has a hem at its open end. Inside the hem is an elastic loop which is used both to hold the top of the bag to the top of the receptacle as well as to close the bag when it is removed from the receptacle. In particular, the elastic is in a highly stretched state when the bag is open. Although a bag of this design would indeed be better retained in position, certain disadvantages of this design have been noted. First, this design is relatively tedious to manufacture. The elastic loop must be stretched and held in place while the hem is formed in the top of the bag. Although these steps would not be impossible, it would certainly add to the cost of manufacturing such bags. As one might expect, it is important to keep the unit cost of can liner bags to an absolute minimum.
Second, this design, i.e. wherein the elastic is stretched when the bag is open, is relatively difficult to package and dispense. Most can liner bags are efficiently packaged in rolls or in a highly folded condition. Because the elastic is relaxed only when the top of the bag is closed, the bags of this design would not be amenable to packaging in rolls and would not be able to be folded so tightly.